StackOverflow2013

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POHow to ping using C sockets
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copied!<ul> <li>Compiler: Code::Blocks(GNU GCC)</li> <li>Platform: Windows(x86) </li> <li>Includes: winsock.h winsock2.h (ws2_32 is linked as well)</li> </ul> <p>I am currently trying to write a program that will read a text file containing a list of IP-Addresses and ping each IP-Addresses respectively. If the host responds to the ping then the host's IP-Address will be copied to a seconded file specified by the user. Unfourtantly this is the first time I have used C's socket library and I cannot find a good tutorial about how to ping using C. From what I understand of the couple tutorials I did find. I need to included a ICMP header, which is a struct containg the ICMP type, code, and checksum, in a IP datagram. But I have no idea how to go about doing so, should I declare the struct myself or is it declared in a header file? I am assuming that it is in a header but the tutorials contradicted each other about exactly where it is declared. I tired including icmp.h and netinet/icmp.h but my compiler complained that they don't exist so I created my own struct.</p> <pre><code> struct echo_request { char type; // Type char code; // Code short checksum; // Checksum short id; // Identification short seq; // Sequence int time; // Time char data[16]; // Data }; </code></pre> <p>I thought that I might be able to get away with it but I wasn't even able to compile my program because my compiler says that in_cksum()(checksum generator) is undefined.</p> <p>To sum up my questions, what header files should I include, how do I create a ping packet, am I using the correct checksum generator function, should a ping be directed to port 80, and should the socket I use be RAW or DGRAM?</p> <p>This is what I have so far, please note that I have purposely left out error checking.</p> <pre><code> int socket_descriptor = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP); struct sockaddr_in address; //Initialize address struct memset(&address, 0, sizeof(address)); //Clear address struct //Declare address address.sin_family = AF_INET; address.sin_addr.s_addr = inet_addr(ipaddress); address.sin_port = htons(80); //Bind socket to address bind(socket_descriptor, (struct sockaddr *)&address, sizeof(address)); //Create packet struct echo_request packet; //See above for declaration of struct memset(packet.data, 1, 16); packet.type = 8; //ECHO_REQUEST packet.code = 0; packet.time = gettime(); packet.checksum = 0; packet.checksum = in_cksum(packet, sizeof(packet)); </code></pre>

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